Lesson 3: Light


Activity 1: Light Sources

Brainstorm a list of light sources in your home and community and record them on a sheet of paper. Share your list with a parent.
Review your child's list of light sources and add any additional ones you can think of.

Activity 2: A Rainbow

Materials: clear glass cup, colored pencils, flashlights (kit)*, mirror (kit), white paper
Sunlight and electric light are white light. So how do rainbows appear in the sky? This experiment will help you split white light into a rainbow of colors using the scientific method. Review the steps of the scientific method below and then conduct the experiment on the page titled "A Rainbow."

NOTE: The mirror for this activity is with your Lesson 3, Activity 7 materials. The first part of this activity requires a sunny day, so if it's cloudy, wait for better weather. The second part of the activity can be done with a flashlight in a dark room, if needed.
  • Problem or Question: What are you going to solve in the experiment? The problem or purpose explains what you hope to accomplish in the investigation.
  • Hypothesis: How do you think it is going to turn out? Use the facts you already know to come up with a guess that makes sense.
  • Materials: List of supplies you will need to complete the experiment.
  • Procedure: What you must do to complete the experiment. Write down the steps you need to follow.
  • Data and Work: Include the tables, observations, and work you did during the experiment. This section is where you keep very careful notes on everything you do and discover. Be sure you write down or draw what really happens, even if it's not what you thought would happen. At the end, look over all your data and think about it very hard. Think of the results of your procedure, or how everything turned out.
  • Conclusion: You must say what you found out during the lab. Figure out whether your results agreed with your hypothesis or not. Put everything you observed together and try to make some sense out of it. The conclusion should answer the problem/questions.
Student Activity Page
Your child will conduct an experiment to try to produce a rainbow.

NOTE: The first part of this activity requires a sunny day, so your child may need to come back to it later if today is cloudy. However, your child can try the mirror variation of the experiment on a cloudy day by using a flashlight in a dark room.

After your child conducts the experiment, review his findings. Explain that the sunlight should have passed through the glass of water and split into rainbow colors. Those colors should appear on the paper. If this did not occur for your child, encourage him to repeat the experiment and try the variation with the mirror.

Explain that white light is made up of many colors mixed together. Isaac Newton proved this over 300 years ago. In a dark room, he directed a beam of sunlight through a small slit and prism. The prism bent (refracted) the white light and a spectrum (rainbow) of colors fanned out. In nature, a rainbow forms when raindrops separate white light.

Activity 3: Colors of Light

Materials: flashlights (kit), note cards (kit), red, blue, and green cellophane (kit), rubber bands (kit)
In the previous experiment you learned that white light is actually made up of many different colors. The primary colors of light are red, green, and blue. These colors combine to form the other colors in a rainbow. Conduct the investigation described on the "Colors of Light" activity page.
Student Activity Page
Tell your child the unusual names for the colors he made during the experiment. Explain that when you shine the light through red and blue cellophane, you make the color magenta, when you shine it through blue and green, you make the color cyan, and when you shine it through red and green you make the color yellow. When you mix all the colors of light, you get white light.